What to keep/deprecate now that Pluto has a built-in presentation mode button

[eford]

@fonsp pointed out in another package

Presentation mode: maybe you could mention the built-in button for presentation mode? > fonsp/Pluto.jl#2660

I replied there (before realizing I should have posted here):
Should we deprecate present_button() now?

We could also consider deprecating ChooseDisplayMode() and undeprecating WidthOverDocs().
Does anyone else have an opinion on this? I
kind of like having both boxes next to each other in ChooseDisplayMode(), but maybe that's just what I've gotten used to.